Friday, January 20, 2012

Disturbing Numbers - Our Obesity Epidemic

I will tell you the numbers first but I hope you stick around for a little more (I moved the technical stuff to the end).

78 Million (plus) American adults are obese, or were obese when the numbers were gathered in 2009-2010.  That is 35% of our population and that should give you pause because the 78 million does not include the additional 78 million who are overweight -  when you combine overweight with obese the number is just over 69 percent.
12 Million (plus) American children and adolescents are obese (2009-2010 data).  The definition of obesity is different in children than adults so we have different percentage points here.  By most accounts it is 12 percent, if the cut off is a little lower it is 16 percent and if we include overweight it is about 30% of children ages 2-19 .  For children we look at percentile rankings (we compare their BMIs to all children that age and if 85, 95 or 97 percent of children are lower, the child is considered overweight or obese, accordingly.  Don't let this confuse you - the words obese and child should not occur in the same sentence.  
There is separate information for infants and toddlers and sadly, about 10 percent of them are also 'obese.'

I am going to share the NCHS data brief with you.  It is not long and contains graphs that show the differences in obesity prevalence (the number of person's who are currently obese) by age group and gender.  Interestingly, the most obese age group for women is age 60 and older and the lowest is the 20-39 age group.  You can read the report for details on differences between men and women, boys and girls and who is catching up to the other.
When you hear the news reports this week - because you will if you haven't already, the main message is that we seem to be stabilizing. 
***My  point for the post today is to clarify what that means.
We are not getting fatter at the same rate as we were ten years ago - we have slowed down, we have not stopped.
Here is an example using small numbers...

At some point,  10 people per year were NEW to the obese category (they joined the already obese people)
then it changed to 15 people per year, and then 20 people per year and it kept going up - every year MORE people joined the group than the year before- but (mostly) no one LEFT the group....
We have now stopped increasing the amount per year that we add, but we still add people every year.... GOT THAT?

technical stuff:
The National Health and Nutrition Examination Survey or NHANES is a nationally representative survey that has been conducted through the National Center for Health Statistics since the 1970s and which is now a continuous survey which collects information in two year cycles.
It has 3 components and complex sampling procedures that allow the type of  extrapolation that I speak of today and that informs the CDC report that I linked.
NHANES is not an experiment.  It is a voluntary study, but people are invited to participate through random selection - in other words, people don't so much volunteer to be in the study as they consent to be in it, once the researchers contact them.
A household interview takes place, some persons also visit a Medical Examination Center (MEC) where lab work is completed, including height and weight, cholesterol readings, etc.  A group of individuals who attend the MEC are also interviewed with a very sophisticated food frequency recall program.  They report 24 hours of food intake and within a week, they get a phone call and complete a second 24 hour recall.  [this information will be invaluable for me and my research, but it really doesn't have anything to do with this particular obesity report - sorry]

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